The Laser Interferometer Gravitational Observatory (LIGO) is an ambitious experimental program designed to directly detect gravitational radiation. The LIGO project began construction in 1998 and was expected to begin taking data in 2000. LIGO will eventually consist of a number of sites worldwide, but as of 2000, two sites neared operational readiness, one near Richland, Washington, and the other near Baton Rouge, Louisiana. Other sites will likely be built in Europe and Asia. As well as attempting to directly verify the existence of gravitational waves, the LIGO observatories will open new ways to observe and measure the composition and evolution of the universe.

Einstein's theory of general relativity relates the curvature of space-time at any point to the mass and energy that exists nearby. General relativity predicts a number of phenomena, such as bending of light by stars and the precession of the planet Mercury...